Compiling SDL frontend

[floren]

I see that there's an SDL frontend defined; is it possible to build Einstein to draw directly to a Linux framebuffer via SDL rather than using FLTK? If so, how would I build that? I tried running cmake -S . -B build -D CMAKE_BUILD_TYPE=Release -D EINSTEIN_SDL3_FRONTEND=ON -DSDL_UNIX_CONSOLE_BUILD=ON but I ended up with a bunch of errors along these lines:

-- Configuring done
CMake Error at CMakeLists.txt:434 (add_executable):
  Target "EinsteinTests" links to target "fltk::fltk" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?


CMake Error at CMakeLists.txt:434 (add_executable):
  Target "EinsteinTests" links to target "fltk::fltk" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?


CMake Error at CMakeLists.txt:434 (add_executable):
  Target "EinsteinTests" links to target "fltk::images" but the target was
  not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at CMakeLists.txt:434 (add_executable):
  Target "EinsteinTests" links to target "fltk::png" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?


CMake Error at CMakeLists.txt:434 (add_executable):
  Target "EinsteinTests" links to target "fltk::z" but the target was not
  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
  an ALIAS target is missing?

Which makes it look like it's still trying to link FLTK.

[MatthiasWM]

The SDL frontend is brand new and currently only supporting Android. I am sure it will be possible to compile the SDL version for iOS and Linux at some point. Is there an issue with the FLTK version?

[floren]

I guess I haven't looked into it that much but I thought FLTK was purely an X toolkit, and I was hoping to run Einstein directly on the framebuffer without involving X -- I'm trying to run on a Raspberry Pi Zero W, so anything that saves memory / cycles is desirable.

[MatthiasWM]

Ah, OK< understood. I that case, the SDL version will be best for you. I can't give a time frame though.

[floren]

I'm going to give it a shot with X, assuming I can get it past compiling CMakeFiles/Einstein.dir/Emulator/JIT/Generic/TJITGeneric_DataProcessingPSRTransfer_ArithmeticOp.cpp.o without OOMing. I've added a gig of swap, we'll see!

[MatthiasWM]

Yeah, some of those JIT files are expanded using cascades macros and become huge when compiled. Maybe you can cross compile form a more powerful machine.

[floren]

I ended up swapping the SD card into an 8GB RPi 4 and it compiled much faster.